ranzcrpart1fandomcom-20200214-history
Vessels/nerves of the neck:All branches of external carotid artery and their relations
The external carotid artery (ECA) is one of the two terminal branches of the common carotid artery. The other terminal branch is the internal carotid (ICA), which is somewhat larger than the ECA Origin and course * The ECA begins at the level of the upper border of the thyroid cartilage (at the level of the fourth cervical vertebra). * It takes a slightly curved course upwards to the space behind the neck of the mandible. * Along its course, it rapidly diminishes in size and as it does so, gives of various branches (see below). * As it enters the parotid gland, it gives rise to its terminal branches, the superficial temporal and maxillary arteries. Branches (Some Anatomists Like F-ing, Others Prefer S&M) The branches of the external carotid artery can be subdivided into groups: * Anterior ** superior thyroid artery: runs vertically downwards with the vein to the upper pole of the thyroid gland with the external laryngeal nerve alongside larynx. Gives infrahyroid, SCM, superior laryngeal and cricothyroid branches. ** '''lingual artery: '''arise near tip of the greater horn of hyoid and form a short loop and pass forward along the greater horn deep to hyoglossus to supply the tongue and floor of the mouth. It is accompanied by the lingual vein. The artery is crossed laterally by the hypoglossal nerve. ** '''facial artery: '''runs upwards on the superior constrictor, deep to digastric and stylohyoid muscles, then deep to submandibular gland. Gives off tonsilar and ascending palatine branch. The artery then makes S bend, curling over submandibular gland and cross the inferior border of mandible to supply the muscle and tissue of the face. * Posterior ** '''Posterior auricular artery: '''arise above the level of digastric muscles often within the parotid gland. It runs up superficial to styloid process and crosses the surface of mastoid process to supply the scalp. Auricular branch supply pinna. In 1/3 a stylomastoid branch enters the stylomastoid foramen and supplies facial nerve. ** '''Occipital artery: '''arise at the level of facial artery. It course back, cross the carotid sheath, deep to posterior belly of digastric, grooves the base of the skull, and pass to apex of posterior triangle to supply the scalp. In 2/3, stylomastoid artery arise from it. * Medial ** '''Ascending pharngeal artery: '''arise above commence of ECA, and runs up the pharynx in front of the preverterbal fascia and deep to ICA. It supplies the pharyngeal wall and soft palate and sends meningeal branches to nearby basal foraminas. * Terminal branches ** (internal) maxillary artery ** superficial temporal artery: arise within the parotid gland, and ascend the posterior root of zygomatic arch, dividing into anterior and posterior branches to supply the scalp. Also supplies, parotid, TMJ and facial structure and outer ear. Variant anatomy * variations in origin arise from the anomalous bifurcation of the common carotid artery - bifurcations may commonly be seen at the level of the cricoid cartilage (C5 level) or at the hyoid bone (C2 level) * Accessory branches ** accessory superior thyroid ** dorsal lingual ** accessory ascending pharyngeal. * variant branching patterns ** linguofacial trunk (incidence ~20%): common origin lingual and facial arteries ** thyrolingual trunk (incidence ~2.5%): common origin superior thyroid and lingual arteries ** thyrolinguofacial trunk (incidence ~2.5%): common origin superior thyroid, lingual and facial arteries ** common occipito-auricular trunk (incidence ~12.5%): common origin occipital and posterior auricular arteries ** ascending pharyngeal may arise from common carotid bifurcation, ECA, or occipital